A flexible polypyrrole/silk-fiber ammonia sensor assisted by silica nanosphere template

• Published in: Sensors and actuators. A. Physical. 2021-01, Vol.317, p.112436, Article 112436
• Main Authors: She, Changkun, Li, Guishun, Zhang, Wenqian, Xie, Guoxing, Zhang, Yu, Li, Lei, Yue, Fangyu, Liu, Shaohua, Jing, Chengbin, Cheng, Ya, Chu, Junhao
• Format: Article
• Language: English
• Subjects: Ammonia; Chemical oxidative polymerization; Chemicals; Nanospheres; NH3 gas sensor; Oxidation; Polypyrrole; Polypyrroles; Recovery time; Relative humidity; Room temperature; Selectivity; Sensors; Silica; Silica nanosphere; Silicon dioxide; Silk; Silk fibers; Temperature
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2020.112436

[Display omitted] •The flexible silk-based PPy sensor for NH3 gas detection was designed.•Silica template helps to improve specific surface area and gas sensor performance.•The gas response of 73.25 % was obtained at 100 ppm with rapid response/recovery time.•The sensor possesses excellent selectivity and reversibility. Flexible polypyrrole (PPy)@silk-fiber and PPy@sponge sensors were fabricated using the silica nanosphere (SiO2 NS) template via a facile in situ chemical oxidation polymerization method. Exposed to 100 ppm NH3 gas at room temperature in 68 ± 5 % relative humidity (RH), the response of the PPy/NS@silk-fiber sensor (73.25 %) was five-fold higher than that of the PPy/NS@sponge sensor (14.51 %). Meanwhile, the recovery time (69 s) of the PPy/NS@silk-fiber sensor was reduced to two-thirds of that (98 s) of the PPy/NS@sponge sensor for 100 ppm NH3. Additionally, the PPy/NS@silk-fiber sensor exhibited excellent reproducibility, flexibility, selectivity, and long-term stability to NH3 at room temperature. The improved gas-sensing properties can be attributed to the high surface area of the flexible PPy/NS@silk-fiber with relative rough hill-like shapes. This investigation indicated that the PPy/NS@silk-fiber is promising sensing material for developing flexible and wearable NH3 sensors.